


home and hearse

by 0neType



Category: Undertale (Video Game)
Genre: Alternate Universe - Underswap, Angst, Dubious Consent, Lack of Communication, M/M, Non-Graphic Violence, One-Sided Relationship, Rape/Non-con Elements, Sibling Incest, death ideation, maybe? i'm not certain if it'd apply in this particular context but please be careful anyways
Language: English
Status: Completed
Published: 2017-02-06
Updated: 2017-02-06
Packaged: 2018-09-22 09:53:31
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 4,294
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/9602555
Author URL: https://archiveofourown.org/users/0neType/pseuds/0neType
Summary: When it comes down to it, Sans would do anything to make his brother happy.





	

**Author's Note:**

> welp ¯\\_(ツ)_/¯

Sans loved his brother. That much was undeniable.

His older brother may have been lazy and slovenly and prone to falling asleep at the worst of times, but he was also the kindest, most genuine monster that Sans knew. Papyrus was the sort of monster you could always count on. He was someone compassionate and full of love. He had so much to give and just…

… not enough people to share it with.

It was no secret to anyone that, between the two of them, Sans had always had a much easier time making and keeping friends. His brother was laid-back and easy to approach, sure, but that didn’t help much when Papyrus couldn’t put himself out there long enough to make a relationship last. He got quiet and awkward around people, often saying things more out of a need to please them than out of any true opinion of his own. Papyrus had acquaintances aplenty, but the number of genuine _friends_ his brother had could be counted on one hand alone—could even be counted on just one finger if Sans counted every phalanx.

That left Papyrus in the upsetting position of having very few people to fall back on when he was feeling low.

His brother was closest to Undyne, but the eccentric scientist was busy with her position as Royal Scientist and couldn’t be expected to be around every single day. Then there was Muffet, and though Sans appreciated that she was there for his brother during those times when Papyrus wouldn’t speak more than a few hushed words without prompting, he didn’t like that the days his brother came home sober were getting fewer and fewer. But the fact remained that the only other person Papyrus was even _remotely_ close to was himself.

And his brother _never_ told him _anything_ about how he was truly feeling.

When it came to talking with Sans, Papyrus would be all jokes and smiles. Conversation was always about something lighthearted and never delved into any solid explanations about things like why his brother woke up screaming at night more often than not. It was a strained, fragile sort of peace. Papyrus was clearly going through the effort of making sure Sans didn’t know he was hurting—as if Sans couldn’t already tell how forced his grins were and how paper-thin his excuses—but Sans couldn’t broach the subject. He didn’t dare attempt to shatter the glass walls his brother had put up between them, fearing a break-down Papyrus wouldn’t be able to bounce back from.

Sans’ soul pained at the thought. It couldn’t be healthy keeping it all bottled up like that.

His brother didn’t deserve to hurt when he already went through so much.

But it was out of his hands if Papyrus refused to share things with him.

So, he took to doing what he _could_ instead.

Sans spent as much of his time with Papyrus as he could spare. He’d drop by his brother’s station in between his practices with Alphys when his brother had a shift nearby. He went with him to Muffet’s when he could, even though he didn’t care much for sweets and wasn’t exactly a big fan of alcohol either. He would pull Papyrus out of his room on days where he didn’t seem to even want to get up out of bed and take him into the kitchen, _demand_ that his brother help him cook something new. He’d flip the channel away from a first look into NTT’s new studio album and turn on a gameshow he knew would catch Papyrus’s interest instead. They’d curl up together on the couch to watch, and Sans would bask in the sound of genuine laughter rumbling from beside him.

It was only right, after all.

If no one else could pick up the slack, _Sans_ would. It was his duty, as Papyrus’s only family, to make sure that he was there whenever his brother needed him.

That’s why,

when it happens,

Sans _knows_ it’s his fault.

He’s home early, back from Alphys’s hours before he’s usually due. Papyrus has the day off today and Sans is excited at the prospect of actually being able to spend a full day with his brother instead of just the few moments they catch together during their mutually busy workweek. He takes the stairs two at a time, practically racing up them and only sparing a second to toss his equipment into his room before bounding towards Papyrus’s door.

He almost immediately opens it too, except a strange sort of feeling comes over him and gives him pause. Stops him long enough for him to hear the low pull of a barely restrained moan make its way through the closed door. And Sans may be the younger brother, but he’s not a child, and there’s no way to mistake that sound as anything other than sexual in nature.

He feels the blush rise to his face even as he drops his hand from the doorknob in embarrassment. He should’ve known, of course, that Papyrus would do something like this when Sans was well away from the house. He’d never really thought of his brother as the libidinous type—seemed like it might be too much effort for Papyrus to put into it more than out of any real thought towards his sexuality—but it’s evident that he’s mistaken as far as that’s concerned.

Sufficiently chagrinned by the turn of events, Sans wills himself calm and makes to go back towards his room.

Except.

Another moan, louder than before, works its way out into the hall and freezes Sans right where he stands. And he can feel his soul twist and roil in a way that makes him feel vaguely nauseous because, just like there was no mistaking the context of the first breathy pant, there’s no mistaking this one either.

“ _Sans_.” His brother pleads again, low and drawn out, and this time, Sans jolts so hard from the sound of it that he bumps up against the railing behind him. His armour clacks loudly against it, deafening in the otherwise quiet surroundings. He instantly stills, hoping that maybe Papyrus didn’t hear it, but the sudden silence from the other side of the door is telling.

Every instinct in him is telling him to run—to hide and to pretend that this never happened—but his body’s trained response is to hold his ground. Alphys hasn’t trained him to flee from a fight, and a fight is exactly what this feels like. Because, despite knowing that this situation is far removed from her coaching on how to hunt down humans and keep the Underground safe, his soul races in his chest like adrenaline has been pumped straight into it, frantic and hard.

So, he shifts his stance and prepares for confrontation anyways.

Still, when the door cracks open and his older brother comes into view, Sans isn’t prepared for the stricken expression that tears across Papyrus’s face at the sight of him. He feels it like a blow to the chest—like an attack to his very _soul_ —as his brother’s form immediately starts to tremble and shake.

No amount of training could’ve readied him for this moment.

“S-sans.” Papyrus says, his voice cracking on his name and making any thoughts of pretending that nothing is out of the ordinary vanish instantly.

There’s no pretending now when it’s so plainly laid out in front of the both of them.

“G-god, Sans, I-I… I don’t—I’m—I-I can’t—”

It’s painful, watching his brother trip and stumble over his words.

It’s even worse when Papyrus starts to hyperventilate, hiccoughing on his sobs, and Sans knows that this is all his fault.

“ _Fuck_ , I didn’t—I didn’t want you to _know_ ,” he gasps, clutching at the front of his hoodie like a lifeline while tears overflow from his sockets and make Sans’ soul pang with awful remorse, “I fucked up. _I’m_ fucked up. I-I’m sorry. I’m sorry. I’m so fucking _sick_ , I—”

“Papyrus,” he says, before he can even think to stop himself; before he can even truly _consider_ what it is he’s saying, “… it’s okay.”

He doubts that Papyrus is in any state to gauge the sincerity of his words, but the guilt rushes through him anyways when the statement only makes his brother cry all the harder. It’s like Papyrus can hear the falsehood in his tone without Sans even intending it, like he knows the words spilled from him on automatic without actual thought put into them. Sans feels his soul constrict as Papyrus falls to his knees, weak and shaking. When his brother speaks, it comes in half-gasps and breathless, winded apologies.

“It’s _not_. I _know_ it’s not. I’m sorry, Sans. I’m s-so messed up. I’m fucking _disgusting_. I-I don’t know _why_ I’m like this, I just…”

But Sans knows exactly why.

His body moves of his own accord, crouching down immediately to get on his brother’s level. He feels his arms wrap around Papyrus as if watching himself from the outside, soothing and shushing him with his voice even as his mind whirls in a frantic panic. He feels sick, he feels nauseous—he wants to throw up but he knows that if he moves away right now, Papyrus will feel rejected. It’ll hurt him. It’ll _hurt_ _Papyrus_ and Sans _hates_ this feeling but he could never, _ever_ hate his brother.

Besides.

This is all Sans’ fault anyways.

This is Sans’ fault because he’s made Papyrus so _dependant_ on him. It’s because, instead of helping his brother be more social and make friends on his own, he’s wrapped Papyrus up in only _his_ presence. He’s _forced_ his brother into becoming so accustomed to him being there for _every, little thing_ that Papyrus’s feelings have been twisted into something distorted and wrong.

“Papy,” he whispers, cutting off his roiling thoughts. The sobbing subsides as his brother stills at the sound of the endearment, “It’s really okay.”

Papyrus looks up at him, silent tears still trickling from his sockets and expression completely uncomprehending.

“Me too.” Sans forces himself to say, ignoring the way his soul churns at the words.

Papyrus stares at him, “W-what?”

“Me too.” He repeats.

And he tells himself that the way Papyrus’s face lights up with hope is worth the bile rises at the back of his unconjured throat.

 

 

Things progress.

It isn’t an overnight change—relationships usually aren’t, despite the kinds of movies his brother likes to watch—and, for the most part, Sans can pretend that things are the same.

He still barges into his brother’s room in the early hours of the morning to shake him awake, and he still drags Papyrus back home at the end of the day after he inevitably falls asleep while drinking at Muffet’s. If anything, the only changes on those fronts are largely _positive_ ; nowadays, Papyrus will often be awake and getting dressed for the day before Sans even knocks at his door. And, while he still makes the trip to Muffet’s frequently, the number of days he passes out in alcoholic incoherence grow smaller and smaller.

Despite how Sans feels about the situation… this has been _good_ for Papyrus.

His brother seems lighter somehow, happy in a way that Sans had almost forgotten than he could be. Papyrus does more and sleeps less, and if all that costs is a few rosy words and chaste kisses then who is Sans to argue?

He finds himself holding onto that thought tightly in between all the moments where he slips away from Papyrus and takes a minute to catch his breath. Where he clenches his fists tight at his sides and lets his eyelights gutter out and just… _blanks_ , relishing in the feeling of nothingness before he has to go back out and guide his big brother very personally through what a romantic relationship is like.

And it’s a weird flip from their usual, to have Sans lead his brother through things. Papyrus has always been the one to take care of them both. Or he _had_ been, up until the point where apathy became his usual and it took hours longer than it should have for his brother to complete even the simplest of tasks. But when it comes to this, while Sans may be the one with the dating manual, Papyrus is the one with very little experience.

So, he leads.

He leads and his brother follows and Sans acts like it’s nothing out of the ordinary.

It’s actually almost funny to see the way his brother reacts to the smallest, barely intimate things. The way Papyrus’s face glows a furious tangerine when his hand grasps Sans’ on the couch as they watch a movie together, for example, is pretty comical. It’s also kind of amusing to hear the way he stutters out a compliment about Sans’ appearance—he always dons his date-wear, clean and pressed; Papyrus might doubt his sincerity otherwise—between every glance he sneaks his way. Or, at least, it _is_ funny up until the point where the mood in the room becomes a little warmer; a little more muted. The point where every soft caress or whispered word from Papyrus catches and sticks between Sans’ ribs and he loses the ability to look at it objectively.

And that’s _dangerous_ , because it feeds something black and wholly unfamiliar somewhere in the pit of his soul. Something inky and dense that sucks away every good feeling like a black hole would do light. And Sans has been dealing with new issues on the daily because of this… _thing_ he’s allowed to take root between them but he’s never _hated_ so deeply. He’s never hated himself with this _relentless_ , clawing dread that screams up from inside him till he’s begging it to just _shut the hell up_ —

In any case, throughout the entirety of their ‘first date’, Sans has to force back the thoughts that scratch at the inside of his skull. But no matter how he pushes, they rake and carve at the inside of his bones till Sans has a permanent headache the refuses to dissipate no matter how much he tries to refocus himself. Papyrus notices his discomfort too.

“You alright, bro?” He asks, concerned and sympathetic as he reaches out with his long, long phalanges and strokes over Sans’ skull in an attempt to soothe the aches.

Sans doesn’t stop him.

“Of course, I am,” he grins instead, smiling brightly up at his brother even when the touches just make the needling pain all the worse, “After all, there’s not much that shakes someone as _sans_ ational as me!”

Papyrus pauses at the sound of his tacky pun, takes in his wide-toothed grin before snorting with laughter. And that would be a relief, it would, except it seems to give his brother enough courage to hesitantly lean in towards him with unmistakeable intent. Sans forgets how to move, stuck horrifically in place as Papyrus crowds over him.

He isn’t sure if his brother notices the way he instantly freezes, but Papyrus only gives him a cautious peck to the forehead before immediately pulling back, embarrassed. Sans forces out a reassuring laugh and hopes to god that it doesn’t sound too much like he’s choking on it.

Papyrus simply squeezes his hand—still wrapped up in his brother’s, between them on the couch—all the tighter, smiling down at him with an unmistakeable fondness.

 

 

He learns that Papyrus is an attentive lover.

Papyrus is all praises and soft admissions when they’re together in bed. He likes to leave kisses all over Sans’ body, the warm press of magic at his teeth leaving his bones buzzing with electric feeling wherever they touch. It crackles over him like static, soothed only by the brush of Papyrus’s bare phalanges as they rub soft circles against every sensitive plane of ivory exposed on his brother’s dingy little mattress.

And they always do this in his brother’s room—they stay clear of Sans’. He doesn’t think he could handle sleeping beneath the same glow-in-the-dark stars that his brother fucks him under. Papyrus never questions it, save for the curious expression that crosses his face each time Sans deliberately redirects them down the hall. But Papyrus doesn’t press and, in a manner becoming more and more familiar to him, Sans plasters a smile to his face and continues to pretend that there’s nothing wrong with this.

“ _God_ , Sans,” his brother pants, rocking his hips up and wrenching another awful moan from him, “You’re so perfect.”

Sans’ hands twist in the bedsheets as pleasure jolts through him, tears prickling at his sockets.

He doesn’t say anything; too afraid he’ll throw up if he opens his mouth.

As per usual, Papyrus fails to notice and Sans fights to push out the bitter thought that says that if his brother truly loved him like he said he did, he’d see something was wrong. He reminds himself that that’s not fair. That the whole _point_ of this is that Papyrus doesn’t notice. That Papyrus is happy and whole and _healing_. And if that’s working then Sans’ has no right to be selfish over a situation he caused in the first place.

“Hahh… _Sans_ …” Papyrus thrusts in deep and Sans feels his pussy throb around him, a shiver wracking its way up his spine.

Papyrus had offered to let Sans top—had said that he was more than fine with switching things off between the two of them—but Sans had turned him down every time. To his brother, he’d said it was because he preferred to let him take control, but the truth is that Sans just can’t imagine it the other way around. It was hard enough to keep himself from freezing up completely when all he had to do was clench a few times for effect and push out a moan or two to keep his brother going. He can’t imagine having to force himself through a role more active that this one, where he’d have to fuck his brother purposefully instead of just laying there and taking what Papyrus gave him.

“I love you so much.” His brother gasps out and Sans shuts his sockets tight to keep from seeing that devoted look in his eyes. It helps, a little, in that it mostly keeps the nausea from rising to high up inside of him. It does nothing to stop the revulsion though.

Nothing really helps with that.

Papyrus is close—Sans can feel the way his rutting starts too lose rhythm and the way his cock twitches inside of him. His grip tightens further in the sheets and Sans wills his soul to stop pounding frantically in his chest. It’s just a little more to go through.

His brother brings his sticky-wet phalanges up to his clit and starts to stroke over Sans in earnest.

“ _Nnn—!_ ” The sudden, additional stimulation is too much for him and his spine immediately arches up off the mattress as he comes, shuddering through his release. His cunt clenches tight around Papyrus’s cock, magic pulsing encouragingly as his brother gives his last few thrusts.

The warm, liquid heat that seeps into him as his brother climaxes makes Sans’ breath hitch in a manner dangerously close to a sob.

Papyrus leans down to rest their foreheads together, flushed and breathless. They stay pressed against each other, coming down in the aftermath. The cum coating his insides starts to dry, sticking to his bones.

Sans feels disgusting.

 

 

The way things are, it’s somewhat of a relief when the human falls down.

Suddenly, everyone’s far too busy thinking over this new development to do much else; him and Papyrus included. And if his brother in particular seems a little wary around the human, it’s not that big a deal—Sans will just spend time with them when Papyrus isn’t around. That way, his brother doesn’t have to be so on edge and Sans gets the added bonus of some time away from him without arousing any suspicion.

The human is nice if a bit strange. For one thing, they never look him too long in the eye. The few instances where they meet each other’s gazes shows Sans a pool of guilt held deep within red irises. He can never quite puzzle it out before the human wrenches their eyes back down to the floor.

It’s fine though. He doesn’t press.

He understands the need to keep secrets.

The human helps him feel more normal than he has in _ages_ , and he finds himself running through Snowdin in a haze of plans and preparations. He whistles while cooking up a meal for his new friend and spends his free time thinking up pranks that’ll trip them up and trap them. The Royal Guard actually seems well within his reach, if only he can contain the human long enough to deliver them to Alphys. For the first time in what seems like forever, he feels his soul thrum in excitement.

So…

… he doesn’t quite know how they end up like this.

“I’m sorry,” the human chokes out, red eyes filled to the brim with tears and hands shaking around the knife they have gripped tightly in their hands, “I-I’m—I’m sorry.”

Sans just stares at them, uncomprehending, ignoring the bar that shows his HP at complete depletion.

“We’re f-friends and I don’t _want_ to hurt you,” they cry out again, tears finally spilling down over their rosy red cheeks, “B-but I’m scared of her! I’m… I’m _scared_ , Sans.”

“Scared of who…? Alphys?” he asks, voice steady even as pain pricks at the numerous cuts the tiny child has left on him and dust starts to shed from his wounds.

The human doesn’t confirm or deny, simply watches him with their pained, troubled eyes over the pointed end of their knife, “Don’t leave me to her. _Please_.”

“You’ll be fine,” Sans tries to reassure, smiling as best he can through the weariness in his soul and taking a step towards them, “It’s not—”

“You’re _wrong!_ ” They shout, looking frantic and frustrated and upset. Sans stills in place as they slash their knife through the air in anger, “This—this isn’t the first time I’ve done this! I’ve killed you before! You just don’t remember!”

He frowns as they speak, questions on the tip of his tongue feeling as grainy and gritty as the ashes gathering in his mouth. But before he can even think to ask them, there’s a flash of imagery in his mind’s eye. Just the briefest glimpse, like a hazy photograph of a time long since forgotten. And he sees it.

_Snow and ice and dust in the wind._

The idea of it chills him, but not in a way that comes from fear. It’s the type of chill that surges out from deep within him, from that black coiling part that he’s kept under wraps for so long. It’s the kind that numbs all sensation in a fog of pure miasmatic finality.

There exists a time and a place where he’s _done_ with all this.

No more pretending.

He can’t think of anything more amazing.

“So, you can really rewind time?” He whispers, awestruck. Because that’s what this is— _time travel_. It’s like something straight out of one of dog-eared paperbacks. And he’s always had a soft spot for sci-fi; especially when it was real.

The human seems taken aback by his attitude, “I-I… Sans… didn’t you hear me? I’ve _killed_ you before. Just like now.”

“That’s okay, I don’t mind,” he says, chipper, and he means it completely.

Papyrus is happy. He’s happy and that’s enough for Sans. He’s done his part already.

He deserves to be a little selfish after all that, doesn’t he?

The way the human is watching him all, wide-eyed and shocked, makes him a little uncomfortable though, so he presses on, “Why did you come back?”

“I… I didn’t want to hurt you. I wanted things to be… different,” they wince, eyeing the lengthy wound they’ve left carved through his chest, “But it doesn’t matter now. Y-you’ve been nothing but good to me and still I—”

“Human,” he says, and his words are a faint echo of before, “… it’s okay.”

And, just like the last time, his words only cause fresh tears to fill up in their eyes, voice rough and patchy as they apologise, “I’m—I’m s-so sorry! I-I’m trying so _hard_ not to hurt a-anyone, but I just—I can’t—I’m… I’m _sorry_.”

They run out of steam, shoulders slumping and knife dropping from their hands as they wrap their arms around themself and fall to their knees. Sans feels sorry for them, wants to go over and hold the child close and console them. It’s impossible though, because his body no longer sees fit to respond to his commands. The human notices it too, hiccoughing sobs breaking from them as Sans’ legs give up from under him, grey dust taking wind.

“Hey,” he says as the last of his body begins to dissipate, soul pounding with an odd, almost manic delight at the thought of all this finally, _finally_ being over, “If we’re really friends… I hope that this time you won’t come back.”

The last thing he sees is the human’s too-bright eyes staring back at him, unreadable with the way his sight goes bleary as his soul beats its end.

 

 

 

 

When he wakes up in Papyrus’s bed, with his brother’s arm slung protectively around him even as he sleeps and the remnants of a dream he can’t quite remember lingering in his head, a part of Sans can’t help but wish he’d never woken up at all.

 

 

 

**Author's Note:**

> idk why all my swapcest ideas are fuckin angsty //lays down ~~my apologies to those of u who like them sweet~~


End file.
